I have a 1995 Royale 88 with only 31000 miles. It runs fine. One cool morning, the tranny did not get out of the first gear, the speedometr stayed at zero and the engine check light came on. This never happened before. I turned around to get home, suddenly the tranny worked fine, the speedometer worked and the engine check light went out. According to the GM service manager it can be the speed sensor on the tranny, but it can also be a few thousand dollar repair. The repair cost can be more than the car value. Any help will be appreciated. Thanks.

 

I don't know if this is relevant but the speedometer on my '87 Delta 88 didn't work until I replaced the fuse for the cruise control.

Can you try swapping it with a sensor from a similar car?, if it makes no difference at least you have eliminated one possible cause.

Roger.

 

Roger, thanks for your reply. Yes, I can see logic between the cruise control and the operation of the speedometer. I never used the cruise control yet, I got the car last December. In my case the tranny stuck in first gear also involved. I do not know much about the car electronics to find the connection between the speedometer and the gear shifting in the tranny. I know that each wheel also has some speed sensor and the combination of all is controlled by the computer. The electronics of today's car is well above my head. I drove the car since everyday and it works OK now. It was only an one time failure. The on-board computer - per the service manager - in this year model does not store any code, so Autozone code reader could not find any code after the light went out. But the GM service manager offered a diagnostic which goes deeper into the computer than Autozone for $95, I am sure they would find something wrong. I tried to locate the speed sensor but I was unable to find it. Can you tell me please where the speed sensor located exactly in my car and how easy to replace it? Now I am just waiting to happen again and I cross my fingers. Thanks again for your help.

 

Even my '86 will store codes. However, it is possible the codes are erased after a certain amount of time of no trouble...
I bet it would be difficult for the GM guys to find an issue if it is intermittant. I bet it would never fail for them if they have my kind of luck.

 

I'm surprised a late model car such as yours doesn't store codes, however I don't get to work on many newer American cars here.
It might be $95 well spent as long as the fault is found by your GM dealer. Ask him if this is a common fault and what causes it normally. In the '90s Vauxhall dealers always carried a good supply of fuel pump relays for Cavalier models as they had a high failure rate.

I would guess the speed sensor would be near the differential, look for a plug in connecter where you would expect a speedo cable to be.

I fixed a non working speedometer on a neighbors car by replacing the sensor which was placed as I described. It was a Suzuki Wagon R+, not a car marketed in north America I suspect, but the principle would be the same. Be warned, to remove it I had to destoy it as it was stuck fast in place, and it cost £65 ($95) to buy. I had my fingers crossed as if it turned out not to be the problem I would have to swallow the cost.


But if your car is running fine now you may have to wait until the fault reappears to make a definite diagnosis. It might quit in the next minute or never again, a real headache for mechanics whenever any car has an intermittent fault.

Hope this helps;
Roger.